US2556973A

US2556973A - Cycler

Info

Publication number: US2556973A
Application number: US5795A
Authority: US
Inventors: Stanley W Nickells
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1948-02-02
Filing date: 1948-02-02
Publication date: 1951-06-12
Anticipated expiration: 1968-06-12

Description

June l2, 1951 s, w, NlCKELLs CYCLER Filed Feb. 2, 1948 nuentor 5TH/utf WN/ckfu Patented June 12, 1951 UNITED STATES PATENT OFFICE CYCLER Delaware Application February 2, 1948, Serial No. 5,795

'4 Claims. (Cl. 201-63) This invention relates to an electrical control device or cycler for periodically operating a power device. More particularly, the invention relates to a cycler suitable for periodically unbalancing a balanced control system which operates fuel feeding means in heating apparatus.

It has been found in the heating of homes and other establishments, that it is highly desirable to more or less continuously supply heat to rooms in which it is desirable to maintain a uniform temperature. In order to obtain this substantially constant supply of heat to a room or rooms in a house, at a temperature which is just suicient to maintain the desired room temperature, it is necessary to supply fuel to the furnace at the proper rate.

In fuel feeding apparatus wherein the fuel feeding means either operatesv at a fixed fuel feeding rate or not at all, it is necessary to provide a control means which periodically turns the fuel feeding means on and off for as long periods of time and as often as is necessary to maintain the necessary rate of fuel flow.

It is in a Wheatstone bridge type of control circuit for an on-off fuelfeeding means that the present invention is particularly suited. In such a system the cycler would be put in series -with an outdoor temperature compensator in one input leg of the bridge, while one or more resistance-type of room thermostat would be positioned in the other input leg of the bridge circuit. In order for the system to operate uniformly over widely varying temperature ranges, it is apparent that the cycler unit must be rugged, sensitive and adjustable to variable conditions, and should operate in la. uniform manner.

Accordingly, it is one of the objects of this invention to provide a cycler control device having means for adjusting the control elements thereof.

Another object of the invention is to provide a cycler which is of sturdy yet inexpensive construction.

Another object of the invention is to provide a cycler Iwhich is so shielded that it assures uniform operation thereof.

A further object of the invention is to provide a cycler which is readily connected to and removed from the control apparatus of which it forms a part.

A still further object of the invention is yto provide a cycler which embodies lall of the above mentioned features in a compact and highly eflicient control device.

Additional objects of the invention will become apparent upon reading the following detailed de- Figure 2 is a side view of the controller with the housing shown in cross-section; and

Figure 3 is a schematic illustration of a control circuit with the cycler therein.

The cycler comprises a body portion II made of a suitable insulating material, such as a molded thermosetting plastic. The body has a base portion I2, in the peripheral edge of which is formed an annular V-shaped groove I3, and a spacer boss I2a forfrninimizing conduction of heat from said body. The body also has a, bobbin portion formed with a plurality of axially spaced, annular grooves I4, longitudinally extending grooves I5 and an end portion I6. The end portion has a recessed portion I'I, extensions of grooves I5, centering lugs I8 and a spacing lug I9. The annular grooves are adapted to be selectively used to hold a coil of heater wire and/or a coil of temperature sensitive wire.

A coil of wire 20, made of metal suitable for use as an electrical heater, such as Manganin wire (84% Cu, 12% Mn and 4% Ni), is selectively positioned in one of the grooves I4 with the ends of the wire passing longitudinally through the grooves I5 beyond the end I6. The wire of this coil is suitably covered with insulating material, such as enamel and nylon. While this coil of wire is shown as being in .a central groove, it is obvious that it may be positioned in any one of the other grooves, depending upon the operating characteristics desired. Also, the size and length of the wire may be varied, to suit the need, or the wire may be divided into a plurality of coils and connected in series or in parallel and positioned in different grooves.

Another coil of wire 2I is positioned in a groove I4, preferably near the base, and is made of a material that has a high temperature coeiicient of resistance, for a purpose to be described hereinafter. This coil is preferably made of nylon covered, enameled balco wire Ni and 30% Fe) and, like the ends of the coil 20, the ends of this coil pass longitudinally through longitudinally extending grooves I5 beyond the end I6. Also, like the coil 20, it may be divided and varied in resistance and selectively positioned in different grooves.

Electrical connector prongs 22 extend longitudinally through the body beyond the base I2 and slightly beyond the end I6. 'I'he portion of the prongs 22 that extend outwardly from the base l2, are adapted to be received by a socket member (not shown) in the control apparatus to be described hereinafter. The boss I 2a spaces the base l2 from the surface of the socket mem- Aber to minimize heat transfer therebetween. The portion of the prongs 22 that extend slightly beyond the end I6, but not as far beyond the end as lug I9, are each connected by soldering, or other suitable means, to one of the ends of the wires forming the coils and 2| that the coils 2U and 2| are detachably con- It is thus seen nected into a control ci-'rcui-t V through theseY prongs, which are non-concentric'ally"spaced ito assure proper insertion in the socketmember.'

In order to make the coils 20 and 2| less affected by drafts of air passin'giove'r therh andv to aid in the transfer of heat uniformly from.

'the closed end of the housing is held from the ends of -the wires wd the ends of thepro'ngs 22 by vmeans of spacing lug lI9. The housing is held in position around the body member by '.swaging the open end thereof inwardly into the V-'shape dv groove i 3 in -the'base |-2.

With the `device completelyassembled as shown in Figures 1 and' 2,y it will be apparent that if thecoil 2t is energized by supplying current thereto yfrom 'asuitable velectrical source, through the'prongs-Z, heat will begene'rated by the coil 28. Heat will then Y be transferred by Aconduction through the body of thedevice to the coil 23|, by radiation and conduction through the housing 23 and -by convection through the air space between -the housing and the body. The lag `in the heattransfer will obviously -bevdetermined by the distance of- 'coil 2| from coil 20. Also, without varying the voltage of the circuit, it 'is `possible 'to vary the wattage of the heater coil or coils and f properly position themAso as to vary the frequencyA of operation Without varying the total cycling resistancedifferential or droop ofthe cycler.

Operation 'In order to more fully understand the utility on the above described cycler, its operation in a control system, such as thatshown in Figure 3 of the drawing, will now be described. A Wheatstone bridge circuit, having apower input transformer 24, has series connected resistance legs 25 and 26 and series connected resistance legs 2l' and 28 connected across the transformer't. An amplifier is connected between the junctions of legs 25 and 2G through the

groundand calibrating resistors

29 and 30 to other resistors in legs-21 and 28.

The leg `25 comprises a fixed resistor 31|-, a'n

ambient temperature compensating resistor -3-2l responding to changes in temperature inthe housing of the control apparatus, a'nd a balancs'istor type of roomv limiters=36 and 3l spaced at 4 different points in the room or house, the temperature of which is to be controlled, and parts of

resistors

29 and 30. Limiter 31, the details of which form no part of this invention, preferably has a switch means therein for varying the resistance thereof for day and night operation.

Leg 28 has thefixed resistor 3'8v and parts of resistors 219 and 3B therein. Y f

Legs `2'! and 28 are joined together and to the Y'ground through resistance 29 and at a Variable point in resistance 3G. The adjustability of the ground connection to resistance 30 properly pro- -'portions` theresistances of legs 21 and 28.

'lsw-itcli,y comprising a relay coil 39 and switch armsdand-iactuated thereby, is connected to the output s'ide'of the amplifier. A power trans- -form'er' 42'is connected through switch arm 4|) to heater 20 of the cycler. The switch arm 4| is adaptediwhen closed, to complete a circuit from a suitable power means (not shown) to a fuel ifeeding means (inoty shown) through 'lead lines 43 andell- The apparatusfis-illustrated in Figure 3 as 'being inla room satisedlcondition for night Aoperation. That is,.aswitch in-limiter 3-1 'is opened, providing. the `greaterfresistance, so 'as torequire a greater drop-:in `ternperature in the room before unbalancing the bridge circuit to` cause operationof'thefurnace. Under this conditionvof the apparatus, the .outdoor compensator Vtl'fmust lower iniresistance. toV balance this increased resi'fstancelinlimiter lbefore'it can unbalance-the 'bridge to cause operation. of the fuel feeding means. I-f the/outside temperature-remains constant, it willbe 'obviousV that the temperature Aof the room must lower anzadditiona'l yamount l'oefore'limiter ST1 can'unbalancethe bridgeto'inie Vtiate operation. ofthe fuel feeding means.

Now assuming that the froom'thermostat is in Tits satisfied condition and theV outside'tempera- -ture is 'suiciently 10W to have'causedthe compensator 34 'to imbalance 4the-bridgecircuitgthe amplifier controlledsswitch 'Willz have closed 'the circuit to the fuel Y"feeding-means and thefheater 'Zit in'the'cycler. .'Ene'rgization of the heater 2E] willi, afterlavpredetermined time lag, heat ycoil 2| 'to increase fitsfresistancefand. balancethe bridge `circuit. Balancing of 'the bridge. circuitl Wl Vcause"d'eenergizationfof the "relayf' and opening of' the circuit to the'fheaterll and: fuelrfeeding means. Y AIf the heat thrown'int'o-theroom during the time -'the burners Were-'inoperationfdoes not cliangethe'resistanceiof the liiniter 36 or 37, and

the "outside temperature 'hasnot: changed: during that time, the cooling offcoil 2|. will aga-inp unbalance the bridgeA circuit to. .again energizeA the 'heater 20 rand'. the ffluelf feeding `means; -It will "thus b'e-Vseen that theffurnace Willl periodically operate sov long .as vthere is anunbalanced condi-- 'tion diie to either ftheroorn'temperature being belowj 'afsatisfied condition Aor fthe outdoor At'emperature being below a predeterminedtempera- 'ture (ius'ua-lly 7.09).. Y

Theid-'uration-a'nd frequency! of operation' of :the fuel feeding means will obviously `.c'leperrd upon the degree ofunbalance of: thei'roomlimiters or "the fout'cioor compensator. The. greater. thefre- 'duction in the resistance: inieith'er f ofl'th'e'se: con;-

trols, the longer it will be necessary forY the heater 2t to be energizedi to increase the resist- 'ance Gif-coil ZJItOftheextent:necessary toballance the bridge circuit; Infmild'we'ather;the'ifurnaice will operate for only short periodslofltimeiandat wideliritervals;4 il'n'lmoderateweatlier, thecycling :frequency increases andi the'4 "onA and loft tim'e periods approach equality at about 50% of the furnace load. The maximum frequency of operation is also reached at this time. In Very cold Weather, the furnace will operate for much longer periods and at shorter off-time intervals.

From the above description of the operation of the control apparatus, it Will readily be seen that in mild weather, the heating plant will supply heat periodically at a very low temperature so as to, in effect, provide constant heating at only a temperature necessary to maintain the desired room temperature. During much colder weather, the furnace will circulate a higher temperature heating medium more frequently to provide a more steady iiow of the heating medium; while during the severest cold weather, the fuel feeding means may continuously operate due to the fact that the temperature responsive resistor 2l in the cycler cannot be heated to the extent necessary to balance the bridge circuit, the resistance of the outdoor compensator 34 having become too low. It will thus be seen that the more nearly continuous supply of heat to the room will be during the bitterest weather. In all conditions of operation of the heating apparatus, stratification of heat layers in the room or house will be effectively prevented due to the regularity of the supply of the heating medium to the room.

In order to obtain the operation of the heating plant, as described above, it is obvious that the control apparatus must have a cyoler therein that is extremely sensitive and rugged and that will operate uniformly.

The cycler of this invention provides all of the above-mentioned characteristics in that the temperature sensing coil 2| is unaffected by drafts, is mounted on a solidly constructed body and has a protective housing. rlhe heat from the heater 29 is carried in three ways from the heater in coil 2i, by conduction through the body of the device, by convection air currents, and by radiation, conduction and radiation again through the housing 23 from the coil 20 to the coil 2l. This assures a regular and uniform transfer of heat between said coils on each operating cycle.

As it is apparent that modifications of the above described cycler can be made without departing from the spirit of the invention, it is to be understood that the scope of the invention is to be determined solely by the appended claims.

I claim as my invention:

1. A timing device comprising a support having a plurality of flanges defining three or more grooves7 a heater type of electrical resistance winding and a temperature responsive resistance control winding disposed in said grooves, one of said windings being disposed in a groove at the extreme end of said support and the other winding being disposed in one or the other of the remaining grooves depending upon the timing period desired, the intermediate groove or grooves being free of windings, and a housing enclosing said support to eliminate any appreciable heat transfer effects from external air currents, the outer dimensions of the flanges between said grooves being substantially less than the internal dimensions of said housing to permit the transfer by convection of heat within said housing between said heater type of winding and said temperature responsive control winding.

2. A control device comprising a bobbin having a plurality of longitudinally spaced peripheral grooves for selectively receiving a smaller number of coils of wire in spaced relationship, a heater coil of wire in one of said grooves, a temperature responsive coil of Wire positioned in a different groove from said heater coil for selectively varying the timing of heat transfer from said heater coil to said responsive coil, a plurality of terminal prongs extending longitudinally through said bobbin to form connection terminals at one end thereof to be received by a socket and to form terminals at the other end thereof to connect said heater coil and said responsive coil to said socket through. said prongs, and a housing spaced from the longitudinal edge and said other end of said bobbin so that said housing will protectively enclose said bobbin and aid in the internal heat transfer between said coils by conduction, convection, and radiation.

3. An electric circuit controller comprising a support having an enlarged end and more than two longitudinally spaced peripheral grooves and a plurality of spacing lingers extending laterally and longitudinally from the other end thereof, terminal prongs extending longitudinally to said support and projecting beyond the end thereof, a heater type of electrical resistor and a temperature responsive electrical resistor separately and selectively positioned in two of said grooves and connected to diiferent prongs at said other end, and a cup-shaped housing spaced from and surrounding said other ends and resistances and sealingly engaging around said enlarged end so that heat may be transferred uniformly from one of said resistances to the other by conduction, convection and radiation without appreciable efects from external air currents.

4. A control device comprising a support having a body portion and a laterally enlarged base at one end thereof and a plurality of outwardly extending spacing fingers at the other end thereof, said body having more than two longitudinal- 1y spaced annular grooves, said base having a spacer stud on its outer end and a peripheral groove therein, connector prongs extending through and outwardlyT from each end of the support, a heater coil encircling said body portion in one of said grooves, a temperature responsive coil also encircling said body portion in another of said grooves, the ends of said coils being connected to different ones of said prongs at said other end, and a cup-shaped housing spaced from and enclosing said coils and body portion and having its open end engaging the periphery of said base and bent inwardly-into said groove and its closed end engaging said spacing fingers.

STANLEY W. N ICKELLS.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,985,691 Pugh Dec. 25, 1934 2,016,660 Weeks Oct. 8, 1935 2,047,796 Ogg July 14, 1936 2,355,680 Ruben Aug. 15, 1944 2,398,333 Shoemaker Apr. 9, 1946 2,520,509 Pfeifer et al Aug. 29, 1950 FOREIGN PATENTS Number Country Date 564,541 France Jan. 4, 1924